The present invention relates to a thermal transfer color printer, and in particular, to a thermal transfer color printer for printing images on a record medium in the form of sheets of paper.
Thermal transfer color printers have been proposed in which colored ink is selectively transferred from a carrier sheet, such as an ink ribbon, to a recording medium (e.g., plain paper or the like) by applying thermal energy to localized areas on the carrier. For example, Japanese Published Patent Application No. 57-174276 discloses a printing system in which a multicolored ink ribbon having nearly the same width as the recording paper is used. Each color area of the ink ribbon is at least as large as the entire area of the picture to be printed and the different color areas are alternately and successively arranged along the length of the ink ribbon. A thermal printhead applies thermal energy to localized areas on the ink ribbon for transferring the colored ink onto the recording paper. In operation, the thermal printhead prints a color image by receiving signals for the various color components in succession. When the first color component signals are received, the corresponding color area of the ink ribbon is advanced by one picture length in synchronization with the advancement of the recording paper. The recording paper then is transported in the reverse or backward direction by one picture length while the ink ribbon is in position to print the next color area. The second color component signals then are received by the thermal printhead and the ink ribbon and recording paper are again advanced by one picture length. Depending on the number of color components, the recording paper is repeatedly transported backward for printing additional color components. The color components are superimposed in the same area of the recording paper to complete the printing of the color image.
Though the above thermal transfer color printer is effective in printing a color image, it has a significant disadvantage if long paper in the form of a roll must be utilized as the recording medium. As a result, color printing on separate sheets of plain paper is not possible.